Analysis For Construction Mechanical Behavior And Load Test Of A Cable Stayed Bridge

Along with the development of domedtic economy and transportation field,more and more bridges are constructioned.Cable-Stayed Bridges become the extremely competitive bridge type which have the characteristics of flexible construction method,large span capacity and handsome appearance.The structural characteristics of Cable-Stayed Bridges determined the construction method and the construction process having very important influence for the force of finished bridge state.Therefore,it has important significance for analying construction stage of Cable-Stayed Bridges to guarantee shuted and normal operationed.In this paper,the main directions is analying construction stage of Cable-Stayed Bridges and load test for Cable-Stayed Bridges.The main research contents and conclusion as follows:(1)The influence matrix method was adopted to computing the Cable-Force of the finished bridge state;the orderly-erecting analysis method was adopted to computing the construction Cable-Force.The results show that: comparisons between theoretical and measured values of cable forces of finished bridges,The maximum error between them was 5.19 %;comparisons between theoretical and measured values of construction Cable-Force.The maximum error between them was 2.59 %.(2)Analyzed of Cable-stayed Bridge construction process.The maximum double cantilever stage,the maximum single cantilever stage and finished bridge state was extracted.Analyzed the internal force,stress and deflection of Cable-stayed Bridge.The results show that: the worst condition of Cable-stayed Bridge was the maximum double cantilever stage.The maximum compressive stress of main girder was 13.87 MPa.(3)Analyzed the influence to Cable-Stayed Bridges in construction stage and finished stage by overall temperature effect,the temperature effect between cable and beam and temperature gradient of beam.The results show that: in the stage of the maximum double cantilever stage,the sorting of influence in Cable-Force,deflection and main tower in the maximum double cantilever stage is: temperature gradient of beam,the temperature effect between cable and beam,overall temperature effect.The sorting of influence in Cable-Force,in the maximum single cantilever stage and the finished bridge state is: the temperature effect between cable and beam,temperature gradient of beam,overall temperature effect.There has little influence in elevation of beam and main tower by three kinds of temperature effect.It was should be control the temperature difference in cable and beam within±5? to reduce the influence of temperature difference to structural internal force.(4)Load test of Cable-Stayed Bridges.The results show that: in the static load,the stress of main girder and main tower was satisfied with standards;in the dynamical Load Test,the measured value of dynamic strain of main girder was less than the theoretical value,the measured value of dynamic deflection of main girder was less than the theoretical value.